It is a request that will make most men stiff with fear - but the perfect penis is needed as part of a display in Iceland.

Now Pall Arason and Tom Mitchell are competing to be the first contributor to the Phallological Museum in Reykjavik.

The men would add to the collection of 280 specimens of penises and penile parts taken from all kinds of animals.

Mr Arason, from Iceland, looked likely to be the first to donate his penis after death.

Then Mr Mitchell, from the US, offered to donate his body part while still alive.

Now their strange quest will be shown as part of a documentary called The Final Member about collector Sigurour 'Siggi' Hjartarson to be released on April 18.

Mr Mitchell, whose penis is called Elmo and tattooed with the Stars and Stripes, explains his determination to donate in the trailer: "I'd like them to know that the largest and best one came from the States."